The present invention relates to a method of driving tubes or pipes into the ground, and also to a tube driver for carrying out the method. The invention further relates to an explosive cartridge for use when carrying out the method and in the tube driving device, and also for loading the ground-entrenched tube with an explosive charge and subsequent blasting of the ground in the region surrounding said tube.
More specifically, the invention relates to a method of driving a tube into the ground with the aid of a driving rod whose length corresponds to the intended depth of the tube penetration, comprising the steps of fitting the tube around the driving rod, holding a generally conical, metallic sacrificial pointed tip, whose base cross-section dimensions contain the outer contour of the tube in impact contact with the forward end of the driving rod, driving the driving rod, together with tube and sacrificial tip into the ground to the depth intended, and withdrawing the driving rod away from the sacrificial tip and out of the ground-entrenched tube.
With regard to the tube driving device, the invention concerns a device for carrying out the method steps of driving a tube into the ground in accordance with the above and comprising a driving rod whose length corresponds to the intended ground penetrating depth of the tube, said tube being fitted around the driving rod, and at the forward end of which driving rod there is arranged a generally conical sacrificial pointed tip whose base cross-section dimensions contain the outer contour of the tube, said tip being intended to be driven into the ground together with the tube.
The inventive explosive cartridge is intended for use with the aforesaid tube driving method and the aforesaid tube driving device, and is also intended for loading the ground-entrenched tube with an explosive charge for subsequent blasting of the ground in the region of the entrenched tube.
Methods and devices for driving tubes and pipes into the ground are earlier known to the art from, for instance, Patent Specifications:
A. SE 46462 PA0 B. SE 46886 PA0 C. U.S. Pat. No. 2,902,832 PA0 D. U.S. Pat. No. 3,231,032 PA0 E. U.S. Pat. No. 3,370,659 PA0 F. U.S. Pat. No. 4,231,435 PA0 G. U.S. Pat. No. 3,261,412 PA0 H. U.S. Pat. No. 4,836,299
Publications A. and B. teach a method of placing an explosive charge in holes pre-drilled in the ground, and exploding the explosive charge to produce post erection holes. The task of placing an explosive charge in such holes is made difficult, because it is impossible to exclude the possibility that the hole will collapse. Publication C. teaches a method in which metal, road-embankment tubes are driven or speared into the ground, by hammering the rear ends of the tubes. This method is unsuitable for use with lightweight tubes and in conjunction with cautious or careful blasting operations. Publication D. teaches a method in which a metal, tubular liner is first driven into the ground, by striking or hammering the tube, whereafter a blasting tube is inserted in the liner and the liner then removed from the ground. This method requires the use of heavy equipment and is also time-consuming. This also applies to the teachings of Publication E., which teaches a method of rotating and hammering a metal tube into the ground and injecting an explosive charge thereinto. A ring-shaped drill bit is knocked-off adjacent the tube orifice and left in the ground, when the tube is withdrawn after use. Publication F. proposes, towards the end of the text, the use of a liner tube to prevent the collapse of holes which are formed in soft ground. The tube is fitted to a hole-forming tip and is driven into the ground together with the tip, by hammering the rear end of the tube with the aid of heavy percussion equipment, whereafter the tip is withdrawn from the liner tube. The large tube dimension required to accommodate the hole-forming tip means that the tube must be subjected to large hammering or impact forces, rendering the method unfavourable in the case of lightweight tubes, since the leading end of the tube is unprotected against the driving forces required. Publication G. evidently presumes the use of heavy pile-driving equipment, where the tube, which is withdrawn after use, rests loosely on a driving tip and accompanies the movement of said tip as the tip is driven into the ground. This ground contact is liable to prevent lightweight tubes from being driven into the ground. Publication H. teaches the application of acoustic resonance for driving into the ground a plastic tube fitted around a driving rod, said rod including an annular sacrificial tip which is less suited to receive impact forces.